Electric energy storage device and electric tool system

ABSTRACT

The disclosure provides an energy storage device comprising four energy units with a same rated voltage and a socket, wherein the four energy units are equally divided into two energy modules, and the socket comprises two voltage output terminals respectively connected with a positive electrode and a negative electrode of the electric energy storage device. The socket is further provided with an in-module control part for switching the connection state of two energy units in the energy modules and an inter-module control part for switching the connection state between the two energy modules. The disclosure provides an electric tool system, wherein the electric tool is provided with a plug coupled with a socket. The energy storage device can provide three output voltages, which can be matched with electric tools with different rated voltages, improves the adaptability of the electric energy storage devices, and reduces the cost.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation Application of PCT applicationNo. PCT/CN2019/114237 filed on Oct. 30, 2019, which claims the benefitof CN201811564279.0 filed on Dec. 20, 2018, CN201811564074.2 filed onDec. 20, 2018, CN201811566089.2 filed on Dec. 20, 2018,CN201811564236.2filed on Dec. 20,2018, CN201822146585.4 filed on Dec. 20, 2018,CN201822146597.7 filed on Dec. 20, 2018 CN201822145919.6 filed on Dec.20, 2018, CN201822146566.1 filed on Dec. 20, 2018, CN201822145933.6filed on Dec. 20, 2018. All the above are hereby incorporated byreference.

FIELD OF THE DISCLOSURE

The disclosure relates to the field of electric tools, in particular toan electric energy storage device and an electric tool using theelectric energy storage device.

DESCRIPTION OF THE PRIOR ART

In the garden machinery and power tool industry, power tools aregenerally has a rated working voltage, which means the whole machinewith different voltage platforms needs battery packs of differentvoltage platforms to provide power, so that different battery packs needto be prepared to adapt to the electric tool with different ratedworking voltages, the cost is increased, and the resource is wasteful.

Therefore, it is necessary to design an improved electric energy storagedevice and an electric tool using the electric energy storage device tosolve the above problems.

SUMMARY

The object of the present disclosure to provide an electric energystorage device which can provide three output voltages, and an electrictool system using the electric energy storage device.

To achieve the above object, the disclosure provides the followingsolution, an electric energy storage device comprises four energy unitswith the same rated voltage, wherein the four energy units are equallydivided into two energy modules; and the electric energy storage deviceis provided with a positive electrode and a negative electrode; and theelectric energy storage device is provided with a socket, wherein thesocket comprises two voltage output terminals respectively connectedwith the positive electrode and the negative electrode, and the socketis provided with an in-module control part corresponding to each energymodule, the in-module control part controls two energy units in theenergy module to be in a parallel connection state or a seriesconnection state and can be switched between the parallel connectionstate and the series connection state, and the socket is provided withan inter-module control part, wherein the inter-module control partcontrols the two energy modules to be in a parallel connection state ora series connection state and can switch between the parallel connectionstate and the series connection state.

In an embodiment, the socket is provided with two in-module controlparts, each in-module control part is provided with two parallelswitches and one series switch, the two parallel switches connect twoenergy units in the energy module in parallel, the series switchconnects two energy units in the energy module in series, and in aninitial state, one kind of the parallel switches and the series switchof the in-module control part is in a conducting state, and the otherkind is in an off state.

In an embodiment, the inter-module control part is provided with twoparallel switches which connect the two energy modules in parallel andone series switch which connects the two energy modules in series, andin an initial state, one kind of the parallel switches and the seriesswitch of the inter-module control part is in a conducting state, andthe other kind is in an off state.

In an embodiment, the series switch or the parallel switch in thein-module control part each are individually arranged in one row; theseries switch of the in-module control part are arranged in one row, andthe two parallel switches are arranged in the other row; or the twoparallel switches and the series switch of the in-module control partare arranged in one row.

In an embodiment, four parallel switches of two in-module control partsare arranged in one row; or four parallel switches and two seriesswitches of two in-module control parts are arranged in the same row.

In an embodiment, the series switch or the parallel switches in theinter-module control part each are individually arranged into a row; theseries switch in the inter-module control part is arranged in one row,and the two parallel switches are arranged in the other row; or the twoparallel switches and the series switch of the inter-module control partare arranged in one row.

In an embodiment, the six parallel switches and the three seriesswitches of the in-module control parts and the inter-module controlpart are transversely arranged into two to three rows.

In an embodiment, each parallel switch and the series switch areprovided with two parts separated left and right, each part is providedwith one contact arm, wherein the two contact arms of the parallelswitch or the series switch in a conducting state are in contact witheach other, and the two contact arms of the parallel switch or theseries switch in a breaking state are separated from each other.

To achieve the above object, the disclosure also provides the followingtechnical solution. An electric tool system includes an electric tooland the electric energy storage device, wherein the electric tool isprovided with a plug which is coupled with the socket, and the plug isprovided with two connection pieces which are respectively andelectrically connected with two voltage output terminals.

In an embodiment, an internal switching part matched with the in-modulecontrol part is arranged on the plug, one of the parallel switch and theseries switch of the in-module control part is a normally closed switch,the other is a normally open switch, and the internal switching partcomprises an insulating part for opening the normally closed switch anda conducting part for conducting the normally open switch, so as tochange the two energy units in the energy module from parallelconnection to series connection or from series connection to parallelconnection.

In an embodiment, an external switching part matched with theinter-module control part is arranged on the plug, one of the parallelswitch and the series switch of the inter-module control part is anormally closed switch, the other is a normally open switch, and theexternal switching part comprises an insulating part for opening thenormally closed switch and a conducting part for conducting the normallyopen switch , so as to change the two energy modules from parallelconnection to series connection or from series connection to parallelconnection.

In an embodiment, a plurality of conductive parts are arranged in anintegrated structure and are respectively contacted with a plurality ofnormally open switches located in the same row, and insulatingseparation parts are arranged between adjacent conductive parts; or theconductive part and the insulating part are arranged into an integratedstructure and are respectively contacted with the normally-open switchand the normally-closed switch located in the same row.

To achieve the above object, the disclosure also provides the followingtechnical solution. An electric tool system includes a low-voltageelectric tool, a medium-voltage electric tool, a high-voltage electrictool, and the electric energy storage device, wherein the low-voltageelectric tool is provided with a low-voltage plug, the low-voltage plugis coupled with the socket and enables four energy units to be in a fullparallel connection state; the high-voltage electric tool is providedwith a high-voltage plug which is coupled with the socket and enablesthe four energy units to be in a full series connection state; themedium-voltage electric tool is provided with a medium-voltage plugwhich is coupled with the socket and enables the four energy units to bein a medium-voltage state that every two energy units are connected inseries and then connected in parallel or every two energy units areconnected in parallel and then connected in series.

In an embodiment, the electric tool system further includes alow-voltage battery pack matched with the low-voltage electric tool, amedium-voltage battery pack matched with the medium-voltage electrictool or a high-voltage battery pack matched with the high-voltageelectric tool.

The beneficial effects of the disclosure are: the electrical energystorage device has a variety of output voltages, which increases theapplication range of the electrical energy storage device and reducesthe cost.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing the connection of four energy unitsof the electric energy storage device according to the first embodiment.

FIG. 2 is a schematic diagram showing an initial circuit connection offour energy units of the electric energy storage device according to thefirst embodiment.

FIG. 3 is a terminal arrangement diagram of the electric energy storagedevice according to the first embodiment.

FIG. 4 is a schematic view showing the connection between the electricenergy storage device and the low-voltage plug according to the firstembodiment.

FIG. 5 is a schematic view showing the structure of a low-voltage plugcoupled to the electric energy storage device of the first embodiment.

FIG. 6 is a schematic view of the electric energy storage device engagedwith the low-voltage plug according to the first embodiment.

FIG. 7 is a schematic circuit diagram of the electrical energy storagedevice when mated with a low voltage plug according to the firstembodiment.

FIG. 8 is a schematic view showing a structure in which the insulatingpart and the conductive part of the low-voltage plug are all integrallyprovided.

FIG. 9 is a schematic view showing a structure in which an insulatingpart of a low-voltage plug is integrally provided and a conductive partis additionally integrally provided.

FIG. 10 is a schematic view showing the connection between the electricenergy storage device and the medium-voltage plug according to the firstembodiment.

FIG. 11 is a schematic view showing the structure of a medium-voltageplug matched with the electric energy storage device to the firstembodiment.

FIG. 12 is a schematic view of the electric energy storage deviceengaged with a medium-voltage plug according to the first embodiment.

FIG. 13 is a schematic circuit diagram of the electric energy storagedevice mated with a medium-voltage plug according to the firstembodiment.

FIG. 14 is a schematic view showing a structure in which an insulatingpart and a conductive part of an in-module control part of amedium-voltage plug are integrally provided.

FIG. 15 is a schematic view showing a structure in which a conductivepart of an in-module control part of a medium-voltage plug is integrallyprovided.

FIG. 16 is a schematic view showing the structure of the electric energystorage device matched with the high-voltage plug according to the firstembodiment.

FIG. 17 is a schematic view showing the connection of four energy unitsof the electric energy storage device according to the secondembodiment.

FIG. 18 is an initial circuit connection schematic diagram of fourenergy units of the electric energy storage device according to thesecond embodiment.

FIG. 19 is a terminal arrangement diagram of the electric energy storagedevice according to the second embodiment.

FIG. 20 is a schematic view showing the structure of the electric energystorage device mated with the low-voltage plug according to the secondembodiment.

FIG. 21 is a schematic view showing the connection between the electricenergy storage device and the medium-voltage plug according to thesecond embodiment.

FIG. 22 is a schematic view showing the structure of a medium-voltageplug mated with the electric energy storage device according to thesecond embodiment.

FIG. 23 is a schematic view of the electric energy storage device matedwith a medium-voltage plug according to the second embodiment.

FIG. 24 is a schematic circuit diagram of the electric energy storagedevice mated with a medium-voltage plug according to the secondembodiment.

FIG. 25 is a schematic view showing the connection between the electricenergy storage device and the high-voltage plug according to the secondembodiment.

FIG. 26 is a schematic view showing the structure of a high-voltage plugcoupled to the electric energy storage device according to the secondembodiment.

FIG. 27 is a schematic view of the electric energy storage deviceengaged with the high-voltage plug according to the second embodiment.

FIG. 28 is a schematic circuit diagram of the electric energy storagedevice matched with the high-voltage plug according to the secondembodiment.

FIG. 29 is a schematic view showing a structure in which an insulatingpart and a conductive part are integrally provided.

FIG. 30 is a schematic view showing the connection of four energy unitsof the electric energy storage device according to the third embodiment.

FIG. 31 is an initial circuit connection schematic diagram of fourenergy units of the electric energy storage device according to thethird embodiment.

FIG. 32 is a terminal arrangement diagram of the electric energy storagedevice according to the third embodiment.

FIG. 33 is a schematic view showing the connection between the electricenergy storage device and the low-voltage plug according to the thirdembodiment.

FIG. 34 is a schematic view showing the structure of a low-voltage plugcoupled to the electric energy storage device according to the thirdembodiment.

FIG. 35 is a schematic cross-sectional view of the electric energystorage device engaged with the low-voltage plug according to the thirdembodiment.

FIG. 36 is a schematic circuit diagram of the electric energy storagedevice matched with the low-voltage plug according to the thirdembodiment.

FIG. 37 is a schematic view showing a structure in which the insulatingpart and the conductive part of the low-voltage plug are integrallyprovided.

FIG. 38 is a schematic view showing a structure in which conductiveparts of the low-voltage plug are integrally provided.

FIG. 39 is a schematic view showing the structure of the electric energystorage device mated with the medium voltage plug according to the thirdembodiment.

FIG. 40 is a schematic view showing the connection between the electricenergy storage device and the high-voltage plug according to the thirdembodiment.

FIG. 41 is a schematic view showing the structure of a high-voltage plugfitted with the electric energy storage device according to the thirdembodiment.

FIG. 42 is a schematic view of the electric energy storage device matedwith a high-voltage plug according to the third embodiment.

FIG. 43 is a schematic circuit diagram of the electric energy storagedevice mated with a high-voltage plug according to the third embodiment.

FIG. 44 is a schematic view showing a structure in which the insulatingpart and the conductive part of the high-voltage plug are integrallyprovided according to the third embodiment.

DETAILED DESCRIPTION

In order to make objects, aspects, and advantages of the disclosure moreapparent, the disclosure will describe in detail with the drawings andspecific examples.

It should be noted that, in the drawings, wherein only structural and/orprocess steps have been shown and described in detail that are pertinentto the disclosure, other details that are not pertinent to thedisclosure have been omitted so as not to obscure the disclosure withunnecessary detail.

Additionally, it should also be noted that the terms “ comprises,comprising”, or any other variation thereof, are intended to cover anon-exclusive inclusion, such that a process, method, article, orapparatus that comprises a list of elements does not include only thoseelements but may include other elements not expressly listed or inherentto such process, method, article, or apparatus.

The disclosure provides an electric energy storage device whichcomprises four energy units with equal voltages, wherein the four energyunits can provide three output voltages through series-parallelcombination. The energy unit refers to an object capable of providingelectric energy, such as a battery cell, a lithium battery or otherenergy carrier, of course a plurality of batteries can be electricallycombined to form one energy unit; such batteries include, but are notlimited to, rechargeable batteries such as lithium batteries,nickel-hydrogen batteries, cadmium-nickel batteries. The rated voltagesof the four energy units are both nV. It should be noted that a measuredvoltage of n ±5% V per energy unit can be considered equal.

In this disclosure, four energy units are equally divided into twoenergy modules, the circuit connection between two energy units in eachenergy module has two selectable states of parallel connection andseries connection, and the circuit connection between two energy modulesalso has two selectable states of parallel connection and seriesconnection. Thus, the four energy units of the electric energy storagedevice have the following four connection states:

two energy units in the energy modules are connected in parallel, thetwo energy modules are connected in parallel, so that all four energyunits are connected in parallel; this state can be simply referred to asa full parallel state, and the output voltage is nV;

two energy units in the energy modules are connected in series, the twoenergy modules are connected in series, so that all four energy unitsare connected in series; this state can be simply referred to as a fullseries state, and the output voltage is 4*nV;

two energy units in the energy modules are connected in series, the twoenergy modules are connected in parallel, this state can be simplyreferred to as an internal series-external parallel state, and theoutput voltage is 2*nV; and

two energy units in the energy modules are connected in parallel, thetwo energy modules are connected in series, this state can be simplyreferred to as an internal parallel external series state, and theoutput voltage is 2*nV.

The third and fourth output voltages are the same, so the electricenergy storage device can output three rated voltages. In addition tothe initial connection state, other connection states can be switched bythe mating corresponding plug. In addition, all of the energy units areengaged in operation in any of the aforementioned connected states.

The specific embodiments of the disclosure will be described below withreference to the drawings.

FIRST EMBODIMENT

As shown in FIG. 1 and FIG. 2, the four energy units of the electricenergy storage device are divided into an energy module 10 a and anenergy module 20 a, each energy module 10 a and 20 a including twoenergy units. The electric energy storage device is provided with asocket and the socket has two voltage output terminals correspondinglyconnected to a total positive electrode and a total negative electrodeof the two energy modules 10 a and 20 a connected in parallel or inseries , respectively a positive terminal 101 a and a negative terminal102 a.

The socket (not shown) of the electric energy storage device comprisestwo in-module control parts and one inter-module control part, whereinthe two in-module control parts are used for respectively controllingthe connection state of two energy units in each energy module 10 a and20 a, and the inter-module control part is used for controlling theconnection state between the energy modules 10 a and 20 a.

The in-module control part corresponding to the energy module 10 aincludes a first series switch 41 a, a first parallel switch 31 a, and asecond parallel switch 32 a. The in-module control part corresponding tothe energy module 20 a includes a second series switch 42 a, a thirdparallel switch 33 a, and a fourth parallel switch 34 a. Each of thein-module control parts is connected to the two energy units in theenergy modules 10 a and 20 a in the same manner, and the followingdescription is an example of the in-module control part corresponding tothe energy module 10 a.

The first series switch 41 a, the first parallel switch 31 a, and thesecond parallel switch 32 a all comprise two contact parts (notnumbered) connected with the electrodes of the energy units, and the twocontact parts of the first parallel switch 31 a and the second parallelswitch 32 a are respectively connected with the electrodes with the samepolarity of the two energy units in the energy module 10 a. As shown inFIG. 1, two contact parts of the first parallel switch 31 a arerespectively connected to the negative electrodes of the two energyunits, and two contact parts of the second parallel switch 32 a arerespectively connected to the positive electrodes of the two energyunits, that is the first parallel switch 31 a and the second parallelswitch 32 a are connected in parallel to the two energy units in theenergy module 10 a. The two contact parts of the first series switch 41a are respectively connected with electrodes of opposite polarities ofthe two energy units, and the other two electrodes of oppositepolarities of the two energy units are respectively connected with theafore mentioned voltage output terminals 101 a, 102 a, that is, thefirst series switch 41 a is connected in series with the two energyunits in the energy module 10 a.

The in-module control part corresponding to the energy module 20 a isprovided with a second series switch 42 a, a third parallel switch 33 a,and a fourth parallel switch 34 a, wherein the second series switch 42 ais connected in series with two energy units in the energy module 20 a,and the third parallel switch 33 a and the fourth parallel switch 34 aare connected in parallel with two energy units in the energy module 20a.

The inter-module control part is connected in a manner similar to thein-module control part, and can be understood to refer to the energymodule as an energy unit, the following is a detailed description of theinter-module control part. Each energy module 10 a, 20 a is provided asa whole with two positive and negative electrodes. The inter-modulecontrol part includes a third series switch 43 a, a fifth parallelswitch 35 a, and a sixth parallel switch 36 a, and both contact parts ofthe fifth parallel switch 35 a and the sixth parallel switch 36 a arerespectively connected to electrodes of the same polarity of the twoenergy modules 10 a, 20 a. As shown in FIG. 1, two contact parts of thefifth parallel switch 35 a are respectively connected with two positiveelectrodes of the two energy modules 10 a and 20 a, two contact parts ofthe sixth parallel switch 36 a are respectively connected with twonegative electrodes of the two energy modules 10 a and 20 a, namely, theparallel switches 35 a and 36 a are connected with the two energymodules 10 a and 20 a in parallel; the two contact parts of the thirdseries switch 43 a are respectively connected to two electrodes ofopposite polarity of the two energy modules 10 a, 20 a, that is, thethird series switch 43 a is connected in series with the two energymodules 10 a and 20 a. The other two opposite polarity electrodes of thetwo energy modules 10 a, 20 a are respectively connected with theaforementioned voltage output terminals 101 a, 102 a as outputstructures.

One kind of the series switch and the parallel switch of the in-modulecontrol part is in on-state, and the other is in off-state. Which meansthat the series switch and the parallel switch of the in-module controlpart can't close simultaneously. If the series switch is closed, theparallel switch is open. In this embodiment, the four parallel switches31 a, 32 a, 33 a, 34 a of the in-module control part are normally openswitches in the off-state, and the two series switches 41 a, 42 a of thein-module control part are normally closed switches in the on-state, sothat the two energy units in the energy modules 10 a, 20 a are initiallyconnected in series.

One kind of the series switch and the parallel switch of theinter-module control part is in on-state, and the other is in off-state.In this embodiment, the parallel switches 35 a, 36 a of the inter-modulecontrol part are normally open switches in off-state, the series switch43 a of the inter-module control part is normally closed switches inon-state, and the energy modules 10 a, 20 a are initially connected inseries. The energy units of the electric energy storage device areinitially in series state with an output voltage of 4 nV, and FIG. 2 isa corresponding circuit diagram.

A terminal structure of a parallel switch and a series switch will bedescribed with reference to FIG. 3. The structure of the two kinds ofswitches is basically the same, each switch comprises two partsseparated from the left and right, each part comprises a main body and acontact arm extending forward from the main body, and the two contactarms together form a contact part. In the embodiment, the series switchis a normally closed switch, namely, two contact arms of the seriesswitch are in a contact conducting state; the parallel switch is anormally open switch, that is the two contact arms of the parallelswitch are in a non-contact open state.

Referring to FIG. 3, in this embodiment, three series switches 41 a, 42a, 43 a and six parallel switches 31 a, 32 a, 33 a, 34 a, 35 a, 36 a oftwo in-module control parts and the inter-module control part arearranged in front and rear rows, and three series switches 41 a, 42 a,43 a are arranged in front and six parallel switches 31 a, 32 a. 33 a,34 a, 35 a, 36 a are located in the rear row and are arrangedtransversely in sequence, and in the left-right direction, each seriesswitch 41 a, 42 a, 43 a and each parallel switch 31 a, 32 a, 33 a, 34 a,35 a, 36 a are independently arranged in one row, wherein each seriesswitch 41 a, 42 a, 43 a are respectively located between twocorresponding parallel switches 31 a, 32 a, 33 a, 34 a, 35 a, 36 a. Thetwo voltage output terminals of the electric energy storage device arearranged up and down in a row, and are respectively a positive terminal101 a arranged on the upper side and a negative terminal 102 a arrangedon the lower side. As a simple variation, the two voltage outputterminals 101 a, 102 a can arrange back and forth or left and right.

Referring to FIGS. 4 to 9 in conjunction with FIG. 1, a low-voltageelectric tool (not shown) operates at nV and has a low-voltage plug (notshown) that mates with a plug of the electrical energy storage device.The low-voltage plug is provided with two connection pieces 71 a and 72a in a monolithic structure, and the two connection pieces 71 a and 72 aare respectively connected with the two voltage output terminals 101 aand 102 a.

The low-voltage plug is also provided with two internal switching partsrespectively corresponding to each of the in-module control parts, theinternal switching parts is used for switching controlling of thein-module control parts so as to change the connection states of the twoenergy units in the energy modules 10 a and 20 a. And the low-voltageplug is also provided with an external switching part corresponding tothe inter-module control part, the external switching part is used forswitching controlling of the inter-module control part so as to changethe connection state between the energy modules 10 a and 20 a. Eachswitching part is provided with an insulating part corresponding to thenormally-closed switch and used for opening the two contact arms, and aconducting part corresponding to the normally-open switch and used forconducting the two contact arms so as to realize the function ofswitching states.

In this embodiment, the two parallel switches of the in-module controlparts are normally open switches, the series switches are normallyclosed switches, and the internal switching part of the control part inthe module corresponding to the energy module 10 a is provided with afirst insulating part 51 a, a first conductive part 61 a and a secondconductive part 62 a; the internal switching part of the in-modulecontrol part corresponding to the energy module 20 a includes a secondinsulating part 52 a, a third conductive part 63 a, and a fourthconductive part 64 a. In addition, the two parallel switches of theinter-module control part are normally open switches and the seriesswitches are normally closed switches, so the external switching part iscorrespondingly provided with a third insulating section 53 a, a fifthconductive section 65 a and a sixth conductive section 66 a. Eachinsulating part and each conductive part are arranged corresponding tothe arrangement of the corresponding parallel switch and thecorresponding series switch.

When the low-voltage plug is matched with the electric energy storagedevice, the two internal switching parts are respectively matched withthe two in-module control parts, the first insulating part 51 a isinserted between the two contact parts of the first series switch 41 a,and the second insulating part 52 a is inserted between the two contactparts of the second series switch 42 a, so that the first series switch41 and the second series switch 42 are disconnected; the firstconductive part 61 a is interposed between two contact parts of thefirst parallel switch 31 a, the second conductive part 62 a isinterposed between two contact parts of the second parallel switch 32 a,the third conductive part 63 a is interposed between two contact partsof the third parallel switch 33 a, and the fourth conductive part 64 ais interposed between two contact parts of the fourth parallel switch 34a. The first parallel switch 31 a, the second parallel switch 32 a, thethird parallel switch 33 a, and the fourth parallel switch 34 a arerespectively conducted, that is, the two internal switching partsrespectively change the two energy units in the two energy modules 10 aand 20 a from series connection to parallel connection.

The external switching part is fitted with the inter-module controlpart, the third insulating part 53 a is inserted between the two contactparts of the third series switch 43 a to turn off the third seriesswitch 43 a, and the fifth conductive part 65 a is inserted between thetwo contact parts of the fifth parallel switch 35 a. The sixthconductive part 66 a is interposed between the two contact parts of thesixth parallel switch 36 a to make the fifth parallel switch 35 a andthe sixth parallel switch 36 a conductive, that is the externalswitching part changes the two energy modules 10 a, 20 a from seriesconnection to parallel connection, so that the four energy units are allconnected in parallel to output a low voltage nV to the low voltagepower tool, of which the circuit diagram is shown in FIG. 7.

It should be noted that the arrangement of the parallel switches and theseries switches in this embodiment may be arranged as desired and shouldnot be so limited. For example, four parallel switches 31 a, 32 a, 33 a,34 a of the two in-module control parts may be arranged in one row, twoseries switches 41 a, 42 a of the two in-module control parts may bearranged in one row, two parallel switches 35 a, 36 a of theinter-module control parts may be arranged in one row, and a seriesswitch 43 a of the inter-module control parts may be arranged in onerow; or the parallel switches 31 a, 32 a, 33 a, 34 a of the twoin-module control parts are arranged in one row, the two series switches41 a, 42 a of the two in-module control parts are arranged in one row,and the two parallel switches 35 a, 36 a and the series switch 43 a ofthe inter-module control parts are arranged in one row; or four parallelswitches 31 a, 32 a, 33 a, 34 a and two series switches 41 a, 42 a ofthe two in-module control parts are arranged in one row, and twoparallel switches 35 a, 36 a and the series switch 43 a of theinter-module control parts are arranged in one row; alternatively, thefour parallel switches 31 a, 32 a, 33 a, 34 a and the series switches 41a, 42 a of the two in-module control parts are arranged in one row, thetwo parallel switches 35 a, 36 a of the inter-module control parts arearranged in one row, and the series switch 43 a of the inter-modulecontrol parts is arranged in one row. In summary, the arrangement ofparallel switches and series switches on an electric energy storagedevice varies widely, and those skilled in the art will appreciate thatvariations in the arrangement are within the scope of this disclosure.

The first, the second, the third, the fourth, the fifth, and the sixthare not limitative to the number and are merely illustrative of thecorresponding relationships, and in fact, the arrangement of theconductive part and the insulating part may be correspondingly arrangedaccording to the terminal arrangement of the electric energy storagedevice, for example, in FIG. 6, the first to sixth conductive parts 61a, 62 a, 63 a, 64 a, 65 a, 66 a each set independently; each conductivepart and each insulating part can also be integrally arranged as aninserting blade 50 a, as shown in FIG. 8; or all the conductive parts 61a, 62 a, 63 a, 64 a, 65 a, and 66 a can be integrally arranged asanother inserting blade 50 a, a separating part 50 made of insulatingmaterials is arranged between adjacent conductive parts, and the threeinsulating parts can be integrally arranged as shown in FIG. 9; or thethree insulating parts are integrally arranged; alternatively, parts ofthe conductive parts may be integrally provided, the remaining parts maybe integrally or separately provided, and a separating part made of aninsulating materials may be provided between the adjacently conductiveparts provided. In summary, the arrangement of the insulating part andthe conductive part can be correspondingly arranged according to thearrangement of the normally-open switch and the normally-closed switchon the electric energy storage device, and the arrangement modes canvary widely, and those skilled in the art will appreciate thatvariations in the arrangement are within the scope of this disclosure.

Referring to FIGS. 10 to 15, a medium-voltage electric tool (not shown)having an operating voltage of 2 nV and having a medium-voltage plug(not shown) mated with a plug of the electric energy storage device isshown. The medium-voltage plug is provided with two internal switchingparts matched with the in-module control part and two connecting pieces71 b and 72 b matched with the two voltage output terminals 101 and 102.

The internal switching part of the medium-voltage plug is basically thesame in structure as the internal switching part of the low-voltageplug, and is arranged corresponding to the in-module control part andused for switching the state of each in-module control part. Theinternal switching part of the module inner control part correspondingto the energy module 10 a comprises a first insulating part 51 b, afirst conductive part 61 b, and a second conductive part 62 b; theinternal switching part of the in-module control part corresponding tothe energy module 20 a includes a second insulating part 52 b, a thirdconductive part 63 b, and a fourth conductive part 64 b.

When the medium-voltage plug is matched with the electric energy storagedevice, the two internal switching parts are respectively matched withthe in-module control parts, so that the two energy units in the twoenergy modules 10 a and 20 a are changed from series connection toparallel connection. The specific matching mode can be referred to thatthe internal switching part in the low-voltage plug is matched with theinternal control part in the two modules, which the detailed descriptionis omitted. In addition, the two energy modules 10 a, 20 a are connectedin series, the circuit diagram of the four energy units is shown in FIG.13, and the medium voltage 2 nV in the electric energy storage device isoutput to the medium voltage power tool.

It should be noted that the aforementioned embodiment is provided withan insulating part corresponding to a normally closed switch and aconductive part corresponding to a normally open switch. It should beunderstood that the first, second, third, and fourth terms herein arenot intended to be limiting in number, but merely illustrative ofcorresponding relationships. The arrangement of the four conductiveparts 61 b, 62 b, 63 b, 64 b and the two insulating parts 51 b, 52 b ofthe two internal switching parts of the medium-voltage plug may becorrespondingly arranged in various forms according to the terminalarrangement of the electric energy storage device, for example, the fourconductive parts 61 b, 62 b, 63 b, 64 b and the two insulating parts 51b and 52 b may all be integrally provided as a plug connector 50 b, justas shown in FIG. 14; or the four conductive parts 61 b, 62 b, 63 b, 64 bare integrally arranged as another plug connector 50 b, and a separationpart 50 made of insulating materials is arranged between the adjacentconductive parts 61 b, 62 b, 63 b, 64 b, as shown in FIG. 15; or thefour conductive parts 61 b, 62 b, 63 b, 64 b are respectively arrangedas shown in FIG. 12; or two insulating parts 51 b, 52 b may beseparately provided, as shown in FIG. 12; of course, the two insulatingparts 51 b, 52 b may be integrally provided. In summary, the arrangementof the insulating part and the conductive part of the internal switchingpart can be correspondingly arranged according to the arrangement of thenormally-open switch and the normally-closed switch on the electricenergy storage device, and the arrangement modes can vary widely, andthose skilled in the art will appreciate that variations in thearrangement are within the scope of this disclosure.

Referring to FIG. 16 in conjunction with FIG. 2, a high-voltage electrictool (not shown) operates at a voltage of 4 nV and has a high- voltageplug (not shown) that mates with a plug of the electrical energy storagedevice. The high-voltage plug is provided with two connection pieces 71c, 72 c respectively matched with the two voltage output terminals 101,102.

In the initial state, two energy units in the energy modules 10 a and 20a of the electric energy storage device are connected in series throughthe in-module control part, the two energy modules 10 and 20 areconnected in series through the inter-module control part, and thecircuit connection of the four energy units is shown in FIG. 2, and thevoltage of the four energy units is 4 nV. Therefore, it is onlynecessary to connect the two connection pieces 71 c, 72 c on thehigh-voltage plug with the two voltage output terminals 101, 102,respectively, to output a high voltage of 4 nV to the high-voltage powertool.

SECOND EMBODIMENT

Referring to FIGS. 17 to 18, the electric energy storage device providesthe second embodiment, wherein the electric energy storage device alsocomprises four energy units with equal voltages, and the voltage of eachenergy unit is nV; the four energy units are equally divided into twoenergy modules 10 d, 20 d, each energy module 10 d, 20 d comprising twoenergy units, and the electrical energy storage device is also capableof providing three output voltages. The electric energy storage deviceis provided with a socket having two voltage output terminalscorrespondingly connected to a total positive electrode and a totalnegative electrode after being connected in parallel or in series withtwo energy modules 10 d and 20 d, respectively a positive terminal 101 dand a negative terminal 102 d.

The socket comprises two in-module control parts and an inter-modulecontrol part, wherein the in-module control parts are used forcontrolling the connection state of two energy units in each energymodule 10 d and 20 d, and the inter-module control part is used forcontrolling the connection state between the energy modules 10 d and 20d. The in-module control part corresponding to the energy module 10 dcomprises two parallel switches 41 d, 42 d, and a series switch 31 d;the inner module control part of the corresponding energy module 20 dcomprises two parallel switches 43 d, 44 d, and a series switch 32 d;the inter-module control part includes two parallel switches 45 d, 46 d,and a series switch 33 d. The specific connection mode of each switch isthe same as that of each switch in the first embodiment, which can referto the first embodiment.

Different from the first embodiment, in the second embodiment, theparallel switches 41 d, 42 d, 43 d, 44 d, 45 d, 46 d are normally closedswitches, and the series switches 31 d, 32 d, 33 d are normally openswitches, so initially, two energy units in the energy modules 10 d, 20d are connected in parallel, and the two energy modules 10 d, 20 d areconnected in parallel. The four energy units are all connected inparallel, outputting a voltage nV through voltage output terminals 101d, 102 d, as shown in FIG. 18.

The structure of each series switch or each parallel switch issubstantially the same as that in the first embodiment, wherein eachswitch comprises two separately arranged contact arms, corresponding tothe embodiment, the two contact arms of the parallel switch are incontact conduction, and the two contact arms of the series switch aredisconnected without contact. In this embodiment, the arrangement of therespective switches is also different from that in the first embodiment.

Referring to FIG. 19, three series switches 31 d, 32 d, 33 d and sixparallel switches 41 d, 42 d, 43 d, 44 d, 45 d, 46 d of the in-modulecontrol parts and the inter-module control part are arranged in aplurality of rows in a forward-backward direction. From left to right,two parallel switches 41 d and 42 d are arranged in one row, twoparallel switches 43 d and 44 d are arranged in one row, and twoparallel switches 45 d and 46 d are arranged in one row; the threeseries switches 31 d, 32 d, 33 d are respectively arranged in a row, arearranged behind the parallel switches 41 d, 42 d, 43 d, 44 d, 45 d, 46d, and are staggered with the three rows formed by the parallel switches41 d, 42 d, 43 d, 44 d, 45 d, 46 d in the left-right transversedirection. The series switch 31 d is located in the far left row. Thevoltage output terminals 101 d, 102 d are located in the far right row.

Referring to FIG. 20 in conjunction with FIG. 17, a low-voltage electrictool (not shown) operates at nV and has a low-voltage plug (not shown)that mates with a socket of the electrical energy storage device. Thelow-voltage plug is provided with two connection pieces 71 d, 72 d. Theconnecting pieces 71 d and 72 d are respectively matched with the twovoltage output terminals 101 d and 102 d, the two energy units in theenergy modules 10 d and 20 d are kept in parallel, the two energymodules 10 d and 20 d are kept in parallel, and nV can be output to thelow-voltage electric tool.

Referring to FIGS. 21 to 23, a medium voltage electric tool (not shown),which has a working voltage of 2 nV and has a medium voltage plug (notshown) that is mutually matched with the plug of the electric energystorage device.

The medium voltage plug is provided with two connection pieces 71 e, 72e cooperating with two output terminals 101 d, 102 d. The medium-voltageplug is provided with an internal switching part matched with thein-module control part and used for switching the control of thein-module control part on the connection states of the two energy unitsin the energy modules 10 d and 20 d. In this embodiment, the internalswitching part comprises two insulating parts and one conducting part,and specifically, the internal switching part of the in-module controlpart corresponding to the energy module 10 d comprises a conducting part61 e and two insulating parts 51 e and 52 e; the internal switching partof the in-module control part corresponding to the energy module 20 dincludes a conductive part 62 e and two insulating parts 53 e, 54 e.

Each insulating part and the conductive part are arranged correspondingto the arrangement of the corresponding parallel switch and the seriesswitch, on the basis that the two parallel switches 41 d and 42 d arelocated in one row, the two insulating parts 51 e and 52 e areintegrally arranged in one row, on the basis that the two parallelswitches 43 d and 44 d are located in one row, the two insulating parts53 e and 54 e are integrally arranged in one row.

When the medium-voltage plug is mated with the socket, the insulatingparts 51 e, 52 e, 53 e, and 54 e respectively disconnect the parallelswitches 41 d, 42 d, 43 d, and 44 d; the conducting parts 61 e and 62 erespectively conduct the series switches 31 d and 32 d, so that twoenergy units in the energy modules 10 d and 20 d are changed fromparallel connection to series connection, the two energy modules 10 dand 20 d are kept in parallel connection, and the four energy units areconnected in parallel after being connected in series in pairs to outputmedium-voltage 2 nV to the medium-voltage electric tool, and thecorresponding connection circuit diagram is shown in FIG. 24.

It should be noted that the aforementioned embodiment is provided withan insulating part corresponding to each normally-closed switch and aconductive part corresponding to each normally-open switch. It should beunderstood that two or four of them are not to be limited in number andare merely illustrative of corresponding relationships, and in fact, thearrangement of the conductive parts and the insulating parts may becorrespondingly arranged according to the terminal arrangement of theelectric energy storage device, and the conductive parts 61 e, 62 e maybe separately arranged as shown in FIG. 23; the conductive parts 61 e,62 e may be integrally provided, and insulating partitions made of aninsulating material are provided between adjacent conductive parts toavoid short circuits. The insulating parts 51 e, 52 e, 53 e, 54 e may beintegrally provided, or may be all separately provided, or may bepartially integrally provided, or may be partially separated, forexample, the insulating parts 51 e, 52 e may be integrally provided, theinsulating parts 53 e, 54 e may be integrally provided, or both may beintegrally provided, as shown in FIG. 23. The conductive part and theinsulating part may also be integrally provided, for example, oneinsulating part made of an insulating material and one conductive partmade of a conductive material. In summary, the arrangement of theinsulating part and the conductive part can be correspondingly arrangedaccording to the arrangement of the normally-open switch and thenormally-closed switch on the electric energy storage device, and thearrangement modes are varied, and those skilled in the art willappreciate that variations in the arrangement are within the scope ofthis disclosure.

Referring to FIGS. 25 to 27, a high-voltage electric tool (not shown),which has a working voltage of 4 nV and has a high-voltage plug (notshown) that is mutually matched with the plug of the electrical energystorage device.

The high-voltage plug is provided with two connection pieces 71 b, 72 bwhich respectively mate with the two output terminals 101 d, 102 d. Thehigh-voltage plug is further provided with an internal switching partmatched with the in-module control part and used for switching thein-module control part to control the connection states of the twoenergy units in the energy modules 10 d and 20 d. In this embodiment,the internal switching part includes two insulating parts and oneconductive part, specifically, the internal switching part of thein-module control part corresponding to the energy module 10 d includesa conductive part 61 f and two insulating parts 51 f, 52 f, and theinternal switching part of the in-module control part corresponding tothe energy module 20 d includes a conductive part 62 f and twoinsulating parts 53 f, 54 f. The structure of the internal switchingpart is consistent with that of the medium-voltage plug and will not bedescribed in detail.

In this embodiment, the high-voltage plug is further provided with anexternal switching part matched with the inter-module control part andused for switching the control of the connection state between theenergy modules 10 d and 20 d by the inter-module control part. In thisembodiment, the external switching part includes a conductive part 63 fand two insulating parts 55 f, 56 f. When the high-voltage plug is matedwith the socket, the internal switching part is matched with thein-module control part, and the two energy units in the energy modules10 d and 20 d are changed from being connected in parallel to beingconnected in series, the specific matching method can refer to thematching of the medium-voltage plug and the socket in this embodiment.The external switching part is matched with the inter-module controlpart, the insulating parts 55 f and 56 f open the parallel switches 45 dand 46 d, the conducting part 63 f conducts and connects the seriesswitch 33 d, the two energy modules 10 d and 20 d are changed fromparallel connection to series connection so as to output high voltage 4nV to the high-voltage electric tool, and a connection circuit diagramof the four energy units is shown in FIG. 28.

It should be noted that the arrangement of the conductive part and theinsulating part can be arranged according to the terminal arrangement ofthe electric energy storage device. The conductive parts 61 f, 62 f, 63f and the insulating parts 51 f, 52 f, 53 f, 54 f, 55 f, 56 f can beintegrated, as shown in

FIG. 29; the conductive part and the insulating part may be separatelyprovided, or the insulating part may be partially or entirely integrallyprovided. The conductive parts may be provided separately as shown inFIG. 27, or provided integrally. In summary, the arrangement of theinsulating part and the conductive part can be correspondingly arrangedaccording to the arrangement of the normally-open switch and thenormally-closed switch on the electric energy storage device, and thearrangement modes are varied, and those skilled in the art willappreciate that variations in the arrangement are within the scope ofthis disclosure.

THIRD EMBODIMENT

Referring to FIGS. 30 to 31, the electric energy storage device providesthe third embodiment, wherein the electric energy storage devicecomprises four energy units with equal voltages, and the voltage of eachenergy unit is nV; the four energy units are equally divided into twoenergy modules 10 h and 20 h, each energy module 10 h and 20 h comprisestwo energy units, and the electric energy storage device can providethree output voltages.

The electric energy storage device is provided with a socket having twovoltage output terminals correspondingly connected to a total positiveelectrode and a total negative electrode after being connected inparallel or in series with two energy modules 10 h and 20 h,respectively a positive terminal 101 h and a negative terminal 102 h.

The socket comprises two in-module control parts and one inter-modulecontrol part, wherein the in-module control part is used for controllingthe connection state of two energy units in each energy module 10 h and20 h, and the inter-module control part is used for controlling theconnection state between the energy modules 10 h and 20 h.The in-modulecontrol part corresponding to the energy module 10 h comprises twoparallel switches 31 h, 32 h and a series switch 41 h, and the in-modulecontrol part corresponding to the energy module 20 h comprises twoparallel switches 33 h, 34 h and a series switch 42 h; the inter-modulecontrol part includes two parallel switches 43 h, 44 h and a seriesswitch 35 h. The specific connection mode of each switch is the same asthat of each switch in the first embodiment, which can refer to thefirst embodiment.

In this embodiment, the parallel switches 31 h, 32 h, 33 h, 34 h of thein-module control part are normally open switches, the series switches41 h, 42 h are normally closed switches, and initially, two energy unitsin the energy modules 10 h, 20 h are connected in series, similar to thein-module control part in the first embodiment. The parallel switches 43h and 44 h of the inter-module control unit are normally closed switchesand the series switch 35 h is a normally open switch. Initially, theenergy modules 10 h and 20 h are connected in parallel, similar to theinter-module control unit of the second embodiment. In this embodiment,four energy units are connected in series by two and then connected inparallel, and the corresponding connection circuit diagram is shown inFIG. 31.

Referring to FIG. 32, the two in-module control parts and theinter-module control part are arranged in the left-right direction. Twoseries switches 41 h and 42 h of the two in-module control parts arearranged in the front row, and four parallel switches 31 h, 32 h, 33 h,and 34 h are arranged in the rear row; in the left-right direction, theseries switch 41 h is located between the two parallel switches 31 h, 32h, and the series switch 42 h is located between the two parallelswitches 33 h, 34 h. The series switch 35 h of the inter-module controlpart is arranged in the rear row, the parallel switch 43 h is arrangedin the front row, and the other parallel switch 44 h and the parallelswitch 43 h are arranged in one row and are arranged between the frontrow and the rear row. In brief, the switch arrangements of the twoin-modules control parts are the same as that in the first embodiment,which can refer to the first embodiment. The switch arrangements of theinter-module control part are the same as that in the second embodimentwhich can refer to the second embodiment.

Referring to FIG. 33 in conjunction with FIG. 35, a low-voltage electrictool (not shown) operates at nV and has a low-voltage plug (not shown)that mates with a plug of the electrical energy storage device. Twoconnection pieces 71 h, 72 h are provided on the low voltage plug. Theconnection pieces 71 h, 72 h cooperate with two voltage output terminals101 h, 102 h. The low-voltage plug is further provided with two internalswitching parts matched with the in-module control part, the internalswitching part corresponding to the energy module 10 h comprises aninsulating part 51 h and conductive parts 61 h and 62 h, the internalswitching part corresponding to the energy module 20 h comprises aninsulating part 52 h and conductive parts 63 h, and 64 h, and theinsulating parts 51 h and 52 h respectively disconnect the series switch51 h , 52 h, the conducting parts 61 h, 62 h, 63 h and 64 h respectivelyconduct the parallel switches 31 h, 32 h, 33 h and 34 h, so that the twoenergy units in the energy modules 10 h and 20 h are changed from seriesconnection to parallel connection, and the specific matching mode of theinternal switching part and the in-module control part can be referredto the first embodiment, which will not be described in detail. The twoenergy modules 10 h, 20 h are kept in parallel, and the energy storagedevice outputs nV to the low-voltage electric tool, and the circuitdiagram is shown in FIG. 36.

It should be noted that the arrangement of the conductive part and theinsulating part can be correspondingly arranged according to theterminal arrangement of the electric energy storage device. Theconductive part and the insulating part can be integrally arranged asshown in FIG. 37; the conducting parts and the insulating parts can beseparately arranged as shown in FIG. 34; the insulating part can bepartially or completely integrally arranged; the conductive parts can beprovided separately or integrally, as shown in FIG. 38. In summary, thearrangement of the insulating part and the conductive part can becorrespondingly arranged according to the arrangement of thenormally-open switch and the normally-closed switch on the electricenergy storage device, and the arrangement modes can vary widely, whichare not enumerated here, and those skilled in the art will appreciatethat variations in the arrangement are within the scope of thisdisclosure.

Referring to FIG. 39 in conjunction with FIG. 30, a medium-voltageelectric tool (not shown) operates at 2 nV and has a low voltage plug(not shown) that mates with a plug of the electrical energy storagedevice. The medium-voltage plug is provided with two connection pieces71 i, 72 i. The two connecting pieces 71 i and 72 i are respectivelymatched with the two voltage output terminals 101 h and 102 h, the twoenergy units in the energy modules 10 h and 20 h are kept in series, thetwo energy modules 10 h and 20 h are kept in parallel, and 2 nV can bedirectly output to the low-voltage electric tool.

Please refer to FIG. 40 to FIG. 42, a high-voltage electric tool (notshown) has a working voltage of 4 nV and has a high-voltage plug (notshown) that is mutually matched with the plug of the electric energystorage device.

The high voltage plug is provided with two connection pieces 71 j, 72 jcooperating with two output terminals 101 h, 102 h. The high-voltageplug is provided with an external switching part matched with theinter-module control part and used for switching the connection statesof the two energy units 10 h and 20 h in the inter-module control part.The external switching part includes a conductive part 65 j and twoinsulating part 53 j, 54 j. When the high-voltage plug is plugged andmatched with the socket, the external switching part is matched with theinter-module control part, the insulating parts 53 j and 54 j open theparallel switches 43 h and 44 h, the conducting part 65 j conducts theseries switch 35 j, so that the two energy modules 10 h and 20 h arechanged from parallel connection to series connection, and the matchingof the external switching part and the inter-module control part isconsistent with that in the second embodiment, which can refer to thesecond embodiment. The two energy units in the energy modules 10 h, 20 hare kept in series, so that the energy storage device outputs a highvoltage of 4 nV to the high-voltage electric tool, and a correspondingconnection circuit diagram is shown in FIG. 43.

It should be noted that the conductive part 65 j of the inter-modulecontrol part in this embodiment and the two insulating parts 53 j, 54 jcan be integrally provided, as shown in FIG. 44; the conductive part 65j and the two insulating parts 53 j, 54 j can also be providedseparately, as shown in FIG. 41. The two insulating parts 53 j, 54 j canbe integrally provided as shown in FIG. 41; the two insulating parts 53j, 54 j can also be provided separately. In summary, the arrangement ofthe insulating part and the conductive part can be correspondinglyarranged according to the arrangement of the normally-open switch andthe normally-closed switch on the electric energy storage device, andthe arrangement modes can vary widely, which are not enumerated here,and those skilled in the art will appreciate that variations in thearrangement are within the scope of this disclosure.

FOURTH EMBODIMENT

The low-voltage electric tool, the medium-voltage electric tool, thehigh-voltage electric tool, and the electric energy storage device ofany of the embodiments described above can form a broader power toolsystem, with the low-voltage plug of the low voltage electric toolcoupled with the socket of the electric energy storage device andleaving the four energy units in full parallel; the high-voltage plug ofthe high-voltage electric tool is coupled with the socket and enablesthe four energy units to be in a full series connection state; and themedium-voltage plug of the medium-voltage electric tool is coupled withthe socket and enables the four energy units to be connected in parallelafter series connection in pairs or connected in series after parallelconnection in pairs in a medium-voltage state.

In addition, the electric tool system includes a conventional lowvoltage battery pack coupled to the low voltage electric tool, aconventional medium voltage battery pack coupled to the medium voltageelectric tool, or a conventional high voltage battery pack coupled tothe high voltage electric tool. Each conventional low-voltage batterypack is provided with a positive electrode and a negative electrode, andcan be matched with two connecting pieces of the low-voltage electrictool, the medium-voltage electric tool and the high-voltage electrictool respectively. The conventional low-voltage battery pack, theconventional medium-voltage battery pack, and the conventionalhigh-voltage battery pack each have a fixed output voltage value.

It is to be noted that the normally-closed switch according to the firstto the third embodiments is a switch of which two contact parts are in acontact state in an initial state to enable an electrode electricallyconnected to the two contact parts to be in a connected state, and theelectrical connection state of the two contact parts can be changed byan external object action to switch the two contact parts from thecontact state to an open state, for example, a normally-closed terminal.The normally-open switch is characterized in that in an initial state,two contact parts of the normally-open switch are in an open state torealize that electrodes electrically connected with the two contactparts are in the open state, and the electrical connection state of thetwo contact parts can be changed through the action of an externalobject, so that the two contact parts are switched from the open stateto the connected state, for example, a normally-open terminal. Ofcourse, normally-open switches are not limited to normally openterminals, nor are normally closed switches limited to normally closedterminals, and embodiments capable of performing the same function arewithin the scope of this disclosure.

Although the disclosure has been described in detail with reference topreferred embodiments, it will be understood by those skilled in the artthat various changes in form and details may be made therein withoutdeparting from the spirit and scope of the disclosure.

What is claimed is:
 1. An electric energy storage device comprising:four energy units with a same rated voltage, which are equally dividedinto two energy modules; a positive electrode and a negative electrode;and a socket, wherein the socket comprises: two voltage output terminalsrespectively connected with the positive electrode and the negativeelectrode; an in-module control part corresponding to each of the energymodules, wherein the in-module control part controls two of the energyunits in the energy module to be in a parallel connection state or aseries connection state and two of the energy units can be switchedbetween the parallel connection state and the series connection state;and an inter-module control part, wherein the inter-module control partcontrols the two energy modules to be in a parallel connection state ora series connection state and the two energy modules can be switchedbetween the parallel connection state and the series connection state.2. The electric energy storage device according to claim 1, wherein thesocket is provided with two in-module control parts, each in-modulecontrol part is provided with two parallel switches and one seriesswitch, the two parallel switches connect two energy units in the energymodule in parallel, the series switch connects two energy units in theenergy module in series, and in an initial state, one kind of theparallel switches and the series switch of the in-module control part isin a conducting state; the other kind is in an off state.
 3. Theelectric energy storage device according to claim 2, wherein theinter-module control part is provided with two parallel switches whichconnect the two energy modules in parallel and one series switch whichconnects the two energy modules in series, and in an initial state, onekind of the parallel switches and the series switch of the inter-modulecontrol part is in a conducting state; the other kind is in an offstate.
 4. The electric energy storage device according to claim 3,wherein the series switch or the parallel switches of the in-modulecontrol part each are individually arranged in one row; the seriesswitch of the in-module control part is arranged in one row, and the twoparallel switches of the in-module control part are arranged in theother row; or the two parallel switches and the series switch of thein-module control part are arranged in one row.
 5. The electric energystorage device according to claim 3, wherein four parallel switches ofthe two in-module control parts are arranged in one row; or fourparallel switches and two series switches of the two in-module controlparts are arranged in the same row.
 6. The electric energy storagedevice according to claim 3, wherein the series switch or the parallelswitches of the inter-module control part each are individually arrangedin one row; the series switch of the inter-module control part isarranged in one row, and the two parallel switches of the inter-modulecontrol part are arranged in the other row; or the two parallel switchesand the series switch of the inter-module control part are arranged inone row.
 7. The electric energy storage device according to claim 3,wherein six parallel switches and three series switches of the in-modulecontrol parts and the inter-module control part are transverselyarranged into two to three rows.
 8. The electric energy storage deviceaccording to claim 3, wherein each of the parallel switches and theseries switch are provided with two parts separated left and right, eachpart is provided with one contact arm, wherein two of the contact armsof the parallel switch or the series switch in a conducting state are incontact with each other, and two of the contact arms of the parallelswitch or the series switch in a breaking state are separated from eachother.
 9. An electric tool system comprising the electric energy storagedevice having: four energy units with a same rated voltage, which areequally divided into two energy modules; a positive electrode and anegative electrode; and a socket, wherein the socket comprises: twovoltage output terminals respectively connected with the positiveelectrode and the negative electrode, an in-module control partcorresponding to each of the energy modules, wherein the in-modulecontrol part controls two of the energy units in the energy module to bein a parallel connection state or a series connection state and two ofthe energy units can be switched between the parallel connection stateand the series connection state, and an inter-module control part,wherein the inter-module control part controls the two energy modules tobe in a parallel connection state or a series connection state and thetwo energy modules can be switched between the parallel connection stateand the series connection state; and an electric tool, wherein theelectric tool is provided with a plug which is coupled with the socket,and the plug is provided with two connection pieces which arerespectively electrically connected with the two voltage outputterminals.
 10. The electric tool system according to claim 9, wherein aninternal switching part matched with the in-module control part isarranged on the plug, one kind of the parallel switch and the seriesswitch of the in-module control part is a normally closed switch, theother kind is a normally open switch, and the internal switching partcomprises an insulating part for opening the normally closed switch anda conducting part for conducting the normally open switch, so as tochange two of the energy units in the energy module from parallelconnection to series connection or from series connection to parallelconnection.
 11. The electric tool system according to claim 10, whereinan external switching part matched with the inter-module control part isarranged on the plug, one kind of the parallel switch and the seriesswitch of the inter-module control part is a normally closed switch, theother kind is a normally open switch, and the external switching partcomprises an insulating part for opening the normally closed switch anda conducting part for conducting the normally open switch, so as tochange the two energy modules from parallel connection to seriesconnection or from series connection to parallel connection.
 12. Theelectric tool system according to claim 11, wherein a plurality of theconductive parts are arranged in an integrated structure that arerespectively contacted with a plurality of the normally open switcheslocated in the same row, and insulating separation parts are arrangedbetween adjacent conductive parts; or the conductive part and theinsulating part are arranged into an integrated structure that arerespectively contacted with the normally open switch and the normallyclosed switch located in the same row.
 13. The electric tool systemcomprising the electric energy storage device having: four energy unitswith a same rated voltage, which are equally divided into two energymodules; a positive electrode and a negative electrode; and a socket,wherein the socket comprises: two voltage output terminals respectivelyconnected with the positive electrode and the negative electrode, anin-module control part corresponding to each of the energy modules,wherein the in-module control part controls two of the energy units inthe energy module to be in a parallel connection state or a seriesconnection state and two of the energy units can be switched between theparallel connection state and the series connection state, and aninter-module control part, wherein the inter-module control partcontrols the two energy modules to be in a parallel connection state ora series connection state and the two energy modules can be switchedbetween the parallel connection state and the series connection state;and a low-voltage electric tool, wherein the low-voltage electric toolis provided with a low-voltage plug which is coupled with the socket andenables the four energy units to be in a full parallel connection state;a medium-voltage electric tool, wherein the medium-voltage electric toolis provided with a medium-voltage plug which is coupled with the socketand enables the four energy units to be in a medium-voltage state thatevery two energy units are connected in series and then connected inparallel or every two energy units are connected in parallel and thenconnected in series; and a high-voltage electric tool, wherein thehigh-voltage electric tool is provided with a high-voltage plug which iscoupled with the socket and enables the four energy units to be in afull series connection state.
 14. The electric tool system according toclaim 13, further comprises a low-voltage battery pack matched with thelow-voltage electric tool, a medium-voltage battery pack matched withthe medium-voltage electric tool, or a high-voltage battery pack matchedwith the high-voltage electric tool.